1. Technical Field
The present invention relates to an image forming method and image forming apparatus using an electrophotographic process.
2. Description of Related Art
In the electrophotographic image forming process, particularly in the electrophotographic color image forming process in recent years, to achieve high-quality color reproducibility by color imposition, there has been widespread use of an image forming process wherein a primary image developed on a photoreceptor is once transferred onto an intermediate transfer member, and is then transferred onto a final printing medium to be fixed thereon (Patent Documents 1 through 3).
To produce a high-resolution image, small-diameter toner of less than 8.0 μm formed by the polymerization method is used as the mainstream toner. The mainstream toner has a greater surface area for its mass and tends to stick to the surface of a photoreceptor and intermediate transfer member. Its transfer efficiency heavily tends to decrease. Thus, there has been widespread use of the method wherein an external additive agent is added to the toner and the toner surface is treated by an external additive agent in order to reduce the adhesion on the toner surface and to improve the transfer efficiency.
In the process of using an intermediate transfer member, treatment of the toner surface by metallic oxide alone is not sufficient to improve transfer efficiency and image quality. Accordingly, metallic soap (aliphatic metallic salt) is directly coated on the surface of the photoreceptor, and metallic soap is contained in the developer, whereby a very thin film of metallic film is formed on the surfaces of the photoreceptor and intermediate transfer member. This arrangement is used to minimize the direct contact between the photoreceptor surface and toner, whereby a desired transfer efficiency and image quality are ensured.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2000-206801
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2006-259581
[Patent Document 3] Japanese Unexamined Patent Application Publication No. 2003-165857